Albert r watts



A, E. WATTS SPARK PLUL Awucmsme man Dic. um.

Patented Apri 26, 1921.

UNITED STATES ALBERT n. warms, or pouver., cumino, canapa.

SPARK-PLUG.

Specification f Letters IIr'atnt.,

Patented `Apr. 26,

Application leil December 6, 1919. Serial No. 343,029.

To all fw /wm it may concern:

Be it known that I, a subject of the King ofv Great Britain, and resident of the town of Dorvali n the Province of Quebec and Dominion of Canada, .have invented certain new and useful Im? proveniente in Spark-Plugs, of which the following is a full, "clear, and exact descrip tion.

the sparking point and is perforated tol admit gas. The insulator may be held in place in the usual manner or by means of the lower end of the .plug which may be formed separate from the body thereof.

In the drawings which illustrate the in.- ventiom- Figures 1. 2, 3 and 4 are vertical. sectional views illustratingr various modifications of the construction.

Referring to the drawings, and more par ticularly to Fig. 1, 11 designates a tubular body having an externally threaded portion 12 adapted to screw into an engine cylinder.- The bore of the body is shouldered at 413 and internally threaded at 14 above the shoulder to receive a nut 15. The insulator 16 is provided, intermediate its ends, with an enlargement 17 which rests upon the shoulder or seat 13 of the body and is engaged by the nut 15 to hold the insulator in place. The engaging surfaces of the insulator, body and nut are preferably frusto-conical and washers 18 of asbestos or the like are provided to cushion the insulator and to form gas-tight joints. Below the enlargement 17 the diameter of the insulator is somewhat less than the bore of the body so that an air cap 19 is formed to assist in preventing short-circuiting of the plug. An electric conducting stem 20 passes through the body,

suitable arrangements being made to prevent gas leakage around the stem such as 'the provision of a recess 21 in the lower end ofthe insulator between the 'bottom of Ammer TE. l/VATTS,

This invention relates to improvements from the construction .shown in which, and afcollar22 0n the stem, a gasket:

23 may; be compressed. The lower end of the stem projects beyondl the `insulator and serves as a `sparking point. The lower end of the body is internally threaded to receive a cap 24 which is provided on its end` and` to:v

curved surface with apertures 25. Thecap carriesl one or more internally projecting..."-

sparkingpints 26. The cap ncloses the" lower end of the insulator and stem, as=will1 be clearly seen, and forms a chamber?"27?"l around the tips of the sparking points conlf.` Acylinder through thej municating with the apertures 25.

In Fig. 2 they body 11 is without any t shoulder 13 and the cap 24 extends farther up in the body than in Fig. 1 and forms at its upper end aseat for the insulator. The nut 15 being unnecessary in this form for the 4insertionf theinsulator it may be omitted as shown'. In other respects the construction of theilug is the sameas that previously describe, 4

In Fig. 43 the plug shown differs only that the cap 24HCI is an integral part of the body 11". l

In Figs 1, 2 and 3 the insulator has been shown as a one-piece device while in Fig. 4 it is constructed in two arts 17 and 17". The body 11c is Jrovide with a pair of seats 13 upon w ich the insulator parts rest and to which they are screwed by the the stem 20. It will thus be seen that the body is held in' compression between the two insulator parts. As a further precau tion the cap 24 may extend suiiiciently far into the .body to hold the lower insulator part 17a against falling into the engine cyl inder if it breaks orif the stem should become disconnected.

Obviously many minor modifications may be made in the structure without departing from the spirit of the invention.

The operation is extremely simple. When gas is compressed in the engine cylinder a portion thereof Hows through the apertures 25 into the chamber 27 and when the igniw tion lcircuit is completed this small charge of gas is exploded and a jet of iame emerges from each of the openings 25 into the gas surrounding the plug. The result is a simultaneous ignition of the gas in all parts of the compression chamber. The jets of flame are'projeoted to all parts of the compres `sion chamber and ignition ofthe gas takes Fig. 1 in f place simultaneously at a dozen or. more points instead of at a single point as when an ordinary spark plug is used. The igni tion is slightly more rapid but, what is more important, it is absolutely certain so that misires with either qvery poor or very rich ymixtures are entirely avoided. Another very important service performed by the perforated body end is that of excluding carbon and oil from the "lower end of the plug proper. The apertures 25 are some distance apart so that the area of the outer cap surface is considerably greater than the combined area of the apertures. Soot formed in the compression chamber will lodge on the outer surface of the cap und practically none will pass through the apertures 25. Any soot which lodges i'n the apertures is blown out by the flame jets at the next ignition. This device is particularly effective in an engine which is over-lubricated or which is burning oil from the base. llt has been demonstrated that a plug constructed according to this invention will, under the above conditions, remain operative at least ten times as long as an ordi- .nary plug. In a properly runningr engine with proper mixture a plug according to this invention should not require cleaning during its lifetime.

Having thus described my invention, what I claim is 1. A spark plug comprising a h'ollovi7 body having the bore thereof restricted adjacent to the upper end of the body to provide an inwardly extending flange, an outer insulator having its lower end' thereof engaged against the upper face of said flange and reduced to extend; past the flange and to provide a shoulderf encircling the reduced 40 portion and supported on the flange, a second insulator contained within said. body having one end enlarged and abutting the opposite face of the flange and recessed to snugly receive the reduced portion of the 46 outer insulator, said enlarged end forming a shoulder facing the lower end of the bore,

an electrode passing through said insulators and provided with means for clamping the saine against the opposite faces of the 50 flange, a removable apertured cap yclosing the lower end of the body and extending into the bore of the body to bear against the shoulder of' the inner insulator to hold the same against escape through the bottom of the body, Vsaid cap forming in conjunction with the lower end of said inner insulator a primary explosion chamber and sparking points carried by the insulator and cap approaching one another Within said chamber.

2. A spark plug comprising a hollow body having the bore thereof restricted to provide an inwardly extending ange, insulators engaging opposite sides of said flange and provided with abutting portions meeting in a plane out of line with the planes containing the opposite sides of the Vange, and electrodes carried respectively by the body and said insulators. 7

In Witness whereof l have hereunto set my hand.

ALBERT E, WATTS.. 

